Opening and closing of stomata is controlled by from Biology Pho

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 Multiple Choice QuestionsMultiple Choice Questions

121.

In a CAM plant, the concentration of organic acid

  • increases during the day

  • decreases or increases during the day

  • increases during night

  • decreases during any time


122.

Chloroplast dimorphism is a characteristic feature of

  • plants with Calvin cycle

  • C4 -plants

  • all plants

  • only in algae


123.

In which type of reactions related to plant photosynthesis peroxisomes are involved?

  • Glycolate cycle

  • Calvin cycle

  • Bacterial photosynthesis

  • Glyoxylate cycle


124.

Example of water soluble plant pigment is

  • chlorophyll- a

  • chlorophyll- b

  • anthocyanin

  • xanthophyll


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125.

Identify the membrane across which the proton (H+) gradient facilitates ATP synthesis in a typical eukaryotic cell

  • plasma membrane

  • mitochondrial inner membrane

  • mitochondrial outer membrane

  • nuclear membrane


126.

Chlorophyll molecules are located in the

  • thylakoid membrane

  • thylakoid lumen

  • stroma

  • inner chloroplast membrane


127.

The correct sequence of organelles in which glycolate and glyoxylate are produced sequentially in photorespiration is

  • chloroplast and mitochondria

  • chloroplast and peroxisome

  • peroxisome and mitochondria

  • peroxisome and chloroplast


128.

Identify the correct statements in relation to C4 photosynthesis.

  • Kranz anatomy is an essential feature for C4 plants

  • C4 plants have higher water use efficiency than C3 plants

  • Photorespiration can be minimised when C3 pathway is in operation

  • Conversion of oxaloacetate to malate occurs in the bundle sheath cells


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129.

C4 pathway is advantageous over C3 pathway in plants as it

  • occurs in relatively low CO2 concentration

  • uses more amount of water

  • occurs in relatively low O2 concentration

  • is less efficient in energy utilisation


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130.

Opening and closing of stomata is controlled by

  • abscisic acid

  • CO2 concentration

  • O2 concentration

  • light intensity


A.

abscisic acid

B.

CO2 concentration

D.

light intensity

Opening and closing of stomata depends upon the turgidity of guard cells. When the plant has excessive water, the guard cells are turgid and stomata opens. It also depends on CO2 concentration. When CO2 concentration is low is photosynthetic parenchyma, stomata open to absorb more gas. Also as the luminosity increases, the rate of photosynthesis also increases leading to stomatal opening.

ABA or Abscisic Acid is a stress hormone that during water stress conditions induces stomatal closing.


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